#include <Wire.h>
#include <LiquidCrystal_I2C_STEM.h>

// Inisialisasi LCD I2C (alamat 0x27, ukuran 16x2)
LiquidCrystal_I2C_STEM lcd(0x27, 16, 2);

int BuzzerPin = 2;
int ledgreen = 3;
int ledred = 4;
int fan = 5;
int sensor = A0;
float gas = 0;

void setup() {
  pinMode(ledgreen, OUTPUT);
  pinMode(ledred, OUTPUT);
  pinMode(fan, OUTPUT);
  pinMode(BuzzerPin, OUTPUT);

  // Inisialisasi LCD I2C
  lcd.init();
  lcd.backlight();

  // Tampilan introduction
  lcd.setCursor(0, 0);
  lcd.print("Gas Sensor");
  delay(1500);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Kelompok B7");
  delay(1500);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Anggota:");
  lcd.setCursor(0, 1);
  lcd.print("Arya Setiawan");
  delay(1500);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Anggota:");
  lcd.setCursor(0, 1);
  lcd.print("Lintang Dyahayuningsih");
  delay(1500);

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Anggota:");
  lcd.setCursor(0, 1);
  lcd.print("M. Febryadi");
  delay(1500);

  lcd.clear();
  lcd.setCursor(2, 0);
  lcd.print("GAS DETECTOR");
  delay(1500);
  lcd.setCursor(0, 1);
  lcd.print("----");
  delay(1000);
  lcd.setCursor(4, 1);
  lcd.print("----");
  delay(1000);
  lcd.setCursor(8, 1);
  lcd.print("----");
  delay(1000);
  lcd.setCursor(12, 1);
  lcd.print("----");
  delay(1000);
  lcd.clear();
}

void loop() {
  gas = analogRead(sensor);
  gas = gas * 100 / 1023;

  lcd.setCursor(0, 0);
  lcd.print("GAS =");
  lcd.print(gas);
  lcd.print(" %   ");

  if (gas > 50) {
    tone(BuzzerPin, 200);
    digitalWrite(ledred, HIGH);
    digitalWrite(ledgreen, LOW);
    digitalWrite(fan, HIGH);
    
    lcd.setCursor(0, 1);
    lcd.print("<< DANGER !!! >>");
  } else {
    noTone(BuzzerPin);
    digitalWrite(ledred, LOW);
    digitalWrite(ledgreen, HIGH);
    digitalWrite(fan, LOW);
    
    lcd.setCursor(0, 1);
    lcd.print("<< SAFE        >>");
  }
  delay(100);
}